Five years after it was announced, Tesla has opened up reservations for its all-electric Semi truck, scheduled to go into production in 2023. On the company’s website, you can make a reservation by paying $5,000 upfront, then $15,000 within 10 days. (Spotted via InsideEVs.) A word of warning, though: the $5k is refundable, but it seems the $20k ain’t.

Now, you’d be forgiven for having forgotten all about Tesla’s Semi, which was announced in 2017 with futuristic concept art and envious specs. The company says the truck will be powered by four independent motors on the rear axles, go 0-60mph in 20 seconds, and have a battery range of either 300 or 500 miles. Prices start at $150,000, and there have been a number of orders from businesses like Walmart and FedEx in the low-dozens range.

But since that 2017 unveiling, Tesla has struggled with production for the Semi — which is understandable considering how quickly its managed to scale up manufacturing on its other EVs. Currently, the truck is scheduled to go into production next year, but we wouldn’t be too surprised if there are further delays (or even spec changes).

What this news really demonstrates, though, is Tesla’s incredible ability to generate cash flow from customers by encouraging them to put down deposits for products that don’t yet exist (a trend that has since been copied by other EV manufacturers). Essentially, paid reservations are a way for the company to take out interest-free loans from fans. So even if the Semi isn’t much closer to production, it’s certainly ready to generate deposits.